Software defined networking (SDN) is a new network architecture featuring decoupling of control and forwarding. For example, a multimedia broadcast/multicast service (MBMS) gateway in an existing enhanced multimedia broadcast/multicast service (eMBMS) system has both a control plane function and a forwarding plane function. After the SDN network architecture is used, the MBMS gateway can be decoupled into a control plane device and a forwarding plane device. The control plane device can control a behavior of the forwarding plane device by using the OpenFlow protocol.
In the OpenFlow protocol, the forwarding plane device uses flow table-based pipeline processing, and a flow table may have multiple flow entries. When the forwarding plane device receives a data packet, if a flow entry that matches the data packet exists in the flow table, the forwarding plane device forwards the data packet according to the flow entry. In this way, the control plane device can control a packet forwarding behavior of the forwarding plane device by adding, modifying, or deleting a flow entry for the forwarding plane device.
A flow entry includes a time field, and the time field records aging time of the flow entry. The forwarding plane device performs ineffectiveness processing on the flow entry at a moment specified by the aging time. In an existing solution, before a flow entry is installed, the control plane device obtains an ineffective moment of the flow entry, and uses duration between the ineffective moment and a current moment as aging time of the flow entry. However, the forwarding plane device starts timing for the aging time after the flow entry is successfully installed, not at a moment at which the control plane device starts timing for the aging time. Consequently, there is a relatively great difference between an actual ineffective moment and a desired ineffective moment of the flow entry. In addition, the OpenFlow protocol does not ensure an execution order of messages, and therefore, the control plane device cannot accurately predict a moment at which the flow entry is successfully installed. It can be learned that in the prior art, processing time of a flow entry is not accurate enough.